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Oh how I laughed today when I opened the e mail from a geotechnical company with an estimate to carry out a soil investigation

has anybody got any info on what sort of money they paid for one. 

 

The spec in their quote was for two percussion driven holes to a depth of 10m

soil sample analysed at their lab and and findings detailed 

 

we have a seperate structural engineer doing the design of the foundations 

so this is just to analyse the soil makeup 

 

when ive stopped laughing I will post up the cost. 

Thanks for any help

pi##ed off from Cirencester. 

 

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£800 inc vat...original quote was £2k inc vat but that was for a 3m depth.  We waited until we had excavated our massive hole (house is dropped down) and then had ground survey, if your site has to be excavated to any depth for slab I would wait no point in testing anything you are going to dig up and cart away. We had to drop a couple of meters from original ground level to where we needed to be for slab.

 

Vat not able to be reclaimed on prof fees either ...makes it more painful!

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£1,400 inc. VAT.  3 holes, 3 samples at 3 depths from each.  The analysis will be in addition as there's a lot of clay on the site that wasn't shown on the British Geological map (or something like that).

 

My chap is based in Bath, so not that far from Cirencester.  Many of the soil survey people I got quotes from were ridiculously expensive.

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Had my Ground Investigation done today :)

 

Used the same chap as @vivienz after the positive recommendation on her blog.

 

I had two quotes and MSS were significantly cheaper. Was quoted £1250 in VAT for two boreholes to 2.8m with SPT testing.

 

Fortunately the results are looking very good and the ground is suitable for a raft foundation. There is a small amount of clay on site but that will be more than removed when we scrape back to the level required for the hardcore.

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41 minutes ago, lizzie said:

I would wait no point in testing anything you are going to dig up and cart away.

 

Im not sure I would second this advice.

My SE asked for bearing capacity at 600mm below slab height. Unless you are digging down metres then a small rig, like which was used on my site today, will easily be able to tell you the  information you are after.

 

I'd want to know sooner rather later if I was going to have to change foundation design to accommodate unsuitable ground conditions.

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I'm hoping that the MBC foundation and slab will be able to compensate for the clay in our soil, but I'd rather know now if it can't in case I need to shift my finances around to compensate for heavier duty foundations.  There's a particular kitchen that I have my eye on, but I'm confirming nothing until I know how much it will cost to get the house out of the ground.

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So the first quote I have had is for 

two test holes down to a depth of ten metres £2200

soil testing at lab.                                                 £350

final analysing and report.                                  £1000

all prices plus vat.  OMFGG. 

 

 

If @vivienz or @willbish could give me some details I would appreciate it. 

Do you think your bloke has the equipment to go to a depth of 10m. 

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33 minutes ago, Russell griffiths said:

So the first quote I have had is for 

two test holes down to a depth of ten metres £2200

soil testing at lab.                                                 £350

final analysing and report.                                  £1000

all prices plus vat.  OMFGG. 

 

 

If @vivienz or @willbish could give me some details I would appreciate it. 

Do you think your bloke has the equipment to go to a depth of 10m. 

If the soil is stiff it won't but then if it's stiff you won't need to go to 10m.

But if you have to go to 10m and he can get to 5-7m using the sampling tubes  you can probe it till you get to 10m. This will give you an indication of the soil strength but you don't get any soil samples. The probe is just a much thinner rod with a point that gets banged in till you get to the depth you need.

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We knew our house had to be sunk down that was a planning condition hence decision to reduce ground levels before testing. We are solid clay its awful. We did our dig out before we appointed frame and slab contractors so there was no issue with calcs for slab. We have standard mbc slab on clay they provided the detail of what they wanted as the prepared base for their slab and we did that from our excavated and surveyed ground level.

 

If we had done  a ground survey and then stripped off circa 3m metres to get down to where we needed to be to start slab it would have been a useless excercise as we would have surveyed mostly ground that was carted away.  We then had ground survey done from level we were starting build from. Makes more sense if you have to excavare any depth and I am more confident that we actaully surveyed what the house sits on not what was muck away. If you have a level site that you are just stripping off the top layer then survey but if not and you can sensibly wait and do it once you get down then it is better.....saves a 10m deep survey perhaps.....

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No site stripping needed house is raised 450mm above existing ground level to account for flood risk. 

We think we are sitting on a couple of metres of fill as I’ve done a test hole with the digger and didn’t like what I found. 

This is our site the lake sits at about 700mm below the grass level, so digging down any more than that normally leaves you with wet feet, the house is to be raised 450above the grass level in the pic, so above the 1 in 100 year flood risk

even though if that lake was to rise more than 300mm half of the south of England would have long disappeared. 

Who are we to argue. 

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Edited by Russell griffiths
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@Russell griffiths that explains a lot.  We had to raise our levels by a similar amount on last house due to flood risk  (next to river flood zone 3). Cost us a fortune at the time  - we had to pile - and I really resented it. Couldnt have the kitchen I wanted nor the gates on the drive as all the money was spent on that. 

 

I spent 20 odd years resenting that extra cost as we never had a hint of flooding then in 2007 when half the country was underwater we stayed dry. It lapped at our thresholds but didnt come in.  I never complained about the extra cost coming out if the ground again!

 

 

 

Edited by lizzie
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All the prices quoted by everyone are what I had in mind

i had estimated between £1200 to £1500 plus vat

going with the thought that they may need to poke down a bit more you could say a couple of grand. 

 

But where the bloody hell did they get £3500 plus vat. Obviously very busy and can be choosing what they do as they also said 3-4 week lead time with another 3 weeks to get the report back. 

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8 hours ago, Russell griffiths said:

All the prices quoted by everyone are what I had in mind

[...] Obviously very busy and can be choosing what they do as they also said 3-4 week lead time with another 3 weeks to get the report back. 

 

They don't need the work @Russell griffiths. We paid £2.5k and that price included extra work asked for on the day (some extra holes)

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Another reason is that having looked at the geological maps of your area they have seen that the ground is very stiff and in order to get to 10m they will need a shell and auger type rig. Bigger rigs means bigger mobilisation costs which could account for the extra costs involved. 

Where did the 10m depth come from as that's a long way down for just a house Foundation?? 

 

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8 hours ago, Declan52 said:

Another reason is that having looked at the geological maps of your area they have seen that the ground is very stiff and in order to get to 10m they will need a shell and auger type rig. Bigger rigs means bigger mobilisation costs which could account for the extra costs involved. 

Where did the 10m depth come from as that's a long way down for just a house Foundation?? 

 

I have no idea where this 10 m comes from, meeting structural engineer tomorrow so will ask some questions 

he has done a house just down the road from ours so he knows the local ground makeup. 

The problem is I think we are on fill, as our site is a former gravel pit I think all the good gear was removed and the site spoil pushed back in. 

 

My neighbour excavated a big hole to dig a pond and he gave up with all the bits of World War Two aeroplanes that he pulled out. 

It seems in the late forty’s early fifties anything you didn’t want you just buried. 

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11 minutes ago, Russell griffiths said:

The problem is I think we are on fill, as our site is a former gravel pit I think all the good gear was removed and the site spoil pushed back in. 

 

Surely that is an even better argument for a proper insulated raft..? if you retain it with a caisson style pile too - some thing like a 6m sheet, then the ground can't move and you can just build up inside it..??

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  • 6 months later...

I have to undertake a borehole 40m depth to determine if there are shallow mine workings, plus install water sampling and gas monitoring points. SPT and percolationtest. Contamination sampling.

First quote - £14,000 yes fourteen thousand plus vat.

A bit too silly.

 

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